1. Field
One or more embodiments described herein relate to a display device.
2. Description of the Related Art
Various display devices have been developed. Many of these display devices include a display panel containing a plurality of pixels and signal lines and a plurality of drivers for driving the display panel. Each pixel may include a switching element connected to a respective signal line, a pixel electrode connected to a respective switching element, and an opposing electrode. The drivers include a gate driver for supplying a gate signal to the display panel, a data driver for supplying a data signal to the display panel, a signal controller for controlling the data driver and the gate driver. Examples of display devices of this type include a liquid crystal display (LCD) and an organic light emitting diode (OLED) display.
The pixel electrode may be connected to the switching element, such as a thin film transistor (TFT), to receive a data voltage. The opposing electrode may be formed on the entire surface of the display panel to receive a common voltage Vcom. The pixel electrode and the opposing electrode may be positioned on the same substrate or on different substrates.
For example, a liquid crystal display may include two display panels which include the pixel electrode and the opposing electrode, and a liquid crystal layer having dielectric anisotropy interposed therebetween. The pixel electrodes may be arranged in a matrix and connected to the switching elements to sequentially receive data voltages for each row of the matrix. The opposing electrode may be formed on the entire surface of the display panel to receive a common voltage Vcom. A desired image may be acquired by applying voltages to the pixel electrode and the opposing electrode. These voltages generate an electric field in the liquid crystal layer. The intensity of the electric field may control transmittance of light passing through the liquid crystal layer.
One type of display device may receive an input image signal from an external graphic controller. The input image signal may include luminance information of each pixel, and each luminance may have a predetermined number. Also, each pixel may receive a data voltage corresponding to desired luminance information. The data voltage applied to each pixel is represented as a pixel voltage based on a difference from the common voltage applied to the common electrode. Each pixel displays luminance expressed by a gray scale value of the image signal according to the pixel voltage. In the case of the liquid crystal display, deterioration generated by applying the electric field in one direction to the liquid crystal layer for a long time may be prevented by inverting the polarity of the data voltage for each frame, for each row, for each column, or for each pixel.
Recently, the resolution of display devices has been increased to produce higher quality images. However, as resolution increases, the charging time of each pixel at the data voltage decreases. Especially in the case where the polarity of the data voltage is inverted, the time taken to charge the data voltage to a target data voltage may be insufficient.
Attempts have been made to compensate for charging time under these circumstances. One attempt involves employing a pre-charge driving method. This method involves transferring a pre-charge voltage before the target data voltage is applied to each pixel, in order to rapidly reach a pixel voltage for representing target luminance when the corresponding pixel is main-charged.